Stochastic DNA Dual-Walkers for Ultrafast Colorimetric Bacteria Detection

Rapid, sensitive, and reliable pathogen detection is growing in importance in human health and safety. In this work, we report a stochastic DNA dual-walker-based colorimetric biosensor for bacterial detection. In the presence of target bacteria, two kinds of released multiple walking strands are allowed for continuous walking on the Au nanoparticle (AuNP)-based 3D track, resulting in destabilized aggregation of AuNP-based probes. The induced color change from red to blue can serve as an analytical signal for colorimetric detection of target bacteria. We demonstrated that this mothed enables sensitive and specific bacterial detection within 15 min due to its ultrafast reaction kinetics and sensitive color change, showing a linear response ranging from 100 to 105 CFU/mL with a limit of detection of 1 CFU/mL. Moreover, we also realized analysis of practical samples using this colorimetric biosensor. Given its features of rapid, sensitive, specific, and reliable analysis, our stochastic dual-walker-based colorimetric biosensor shows much promise in point-of-care testing for bacteria detection.